BACKGROUND:In 1998, the Storting unanimously adopted the introduction of nationwide mammography screening in Norway. Mammography screening has been the subject of scientific debate, but there has been little research on the political arguments for a public screening programme. In this article I analyse the arguments put forward at that time for nationwide mammography screening. MATERIAL AND METHOD:A document analysis of proposals to the Storting was performed, and recommendations and minutes of debates in the Storting that dealt with nationwide mammography screening. The documents are from the period February-June 1998. RESULTS:The Storting was unanimously in favour of introducing a nationwide breast cancer screening programme. The debate consisted of four main lines of argument: 'breast cancer mortality and the effect of mammography screening', 'women's health', 'justice and equality of healthcare services', and that 'private service providers offer the solution for insufficient equipment and personnel'. The effect of mammography screening on breast cancer mortality permeated the debate. Problematic aspects of screening were not discussed. INTERPRETATION:The fact that early detection affects breast cancer mortality was an underlying premise in the debate on nationwide mammography screening in the Storting in 1998. Since its introduction, mammography screening has been the subject of scientific debate. This has not undermined the political will to maintain the mammography programme, and the introduction of a new screening programme for colon cancer has now been adopted.